Add tvOS Top Shelf extension

Surfaces Continue Watching, Recent Feed, and Recent Bookmarks in the
Apple TV Home top shelf when Yattee is focused. Tapping a tile opens
the video via the existing yattee://video/{id} deep link.

- New YatteeTopShelf app extension target (tvOS only). LD_ENTRY_POINT is
  overridden to _NSExtensionMain; the tv-app-extension product type
  defaults to _TVExtensionMain which is for the pre-tvOS-13 legacy API
  and crashes modern TVTopShelfContentProvider subclasses at launch.
- Main app writes per-section JSON snapshots (capped at 10 items each)
  to a shared App Group UserDefaults suite after bookmark, watch-history,
  and feed-cache changes, plus an initial write on launch.
- Enabled-sections list is mirrored to the same App Group so the
  extension can respect the user's selection without touching SwiftData.
- Settings → Top Shelf (tvOS only) lets the user toggle sections.
- Deep link playback shows a loading toast while video details are
  fetched, and an error toast if no source is configured.

YatteeTopShelf/AppGroup.swift

@@ -0,0 +1,10 @@
+import Foundation
+
+enum AppGroup {
+    static let identifier = "group.stream.yattee.app.shared"
+    static let enabledSectionsKey = "topShelf.enabledSections"
+
+    static var defaults: UserDefaults {
+        UserDefaults(suiteName: identifier) ?? .standard
+    }
+}

YatteeTopShelf/Info.plist

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>NSExtension</key>
+	<dict>
+		<key>NSExtensionPointIdentifier</key>
+		<string>com.apple.tv-top-shelf</string>
+		<key>NSExtensionPrincipalClass</key>
+		<string>$(PRODUCT_MODULE_NAME).TopShelfContentProvider</string>
+	</dict>
+</dict>
+</plist>

YatteeTopShelf/TopShelfContentProvider.swift

@@ -0,0 +1,38 @@
+import TVServices
+
+class TopShelfContentProvider: TVTopShelfContentProvider {
+    override func loadTopShelfContent(completionHandler: @escaping (any TVTopShelfContent) -> Void) {
+        let defaults = AppGroup.defaults
+        let enabled = TopShelfSnapshot.enabledSections(from: defaults)
+
+        let collections: [TVTopShelfItemCollection<TVTopShelfSectionedItem>] = enabled.compactMap { section in
+            let items = TopShelfSnapshot.read(section: section, from: defaults)
+            guard !items.isEmpty else { return nil }
+            let sectioned = items.map { makeItem(from: $0, in: section) }
+            let collection = TVTopShelfItemCollection(items: sectioned)
+            collection.title = section.localizedTitle
+            return collection
+        }
+
+        completionHandler(TVTopShelfSectionedContent(sections: collections))
+    }
+
+    private func makeItem(from item: TopShelfItem, in section: TopShelfSection) -> TVTopShelfSectionedItem {
+        let sectioned = TVTopShelfSectionedItem(identifier: "\(section.rawValue).\(item.videoID)")
+        sectioned.title = item.title
+        sectioned.imageShape = .hdtv
+        if let url = item.thumbnailURL.flatMap(URL.init(string:)) {
+            sectioned.setImageURL(url, for: .screenScale1x)
+            sectioned.setImageURL(url, for: .screenScale2x)
+        }
+        if let deepLink = URL(string: item.deepLinkURL) {
+            sectioned.displayAction = TVTopShelfAction(url: deepLink)
+            sectioned.playAction = TVTopShelfAction(url: deepLink)
+        }
+        if section == .continueWatching,
+           let progress = item.progressSeconds, item.duration > 0 {
+            sectioned.playbackProgress = max(0, min(1, progress / item.duration))
+        }
+        return sectioned
+    }
+}

YatteeTopShelf/TopShelfSection.swift

@@ -0,0 +1,32 @@
+import Foundation
+
+// Must stay in sync with Yattee/Core/Settings/TopShelfSection.swift.
+enum TopShelfSection: String, Codable, CaseIterable, Sendable {
+    case continueWatching
+    case recentFeed
+    case recentBookmarks
+
+    var localizedTitle: String {
+        // The extension doesn't share the main app's string catalog, so we
+        // ship English fallbacks here. Keep in sync with
+        // Localizable.xcstrings entries of the same keys.
+        switch self {
+        case .continueWatching:
+            return String(localized: "home.section.continueWatching", defaultValue: "Continue Watching")
+        case .recentFeed:
+            return String(localized: "home.section.feed", defaultValue: "Feed")
+        case .recentBookmarks:
+            return String(localized: "home.section.bookmarks", defaultValue: "Bookmarks")
+        }
+    }
+
+    var snapshotKey: String {
+        switch self {
+        case .continueWatching: return "topShelf.continueWatching"
+        case .recentFeed: return "topShelf.recentFeed"
+        case .recentBookmarks: return "topShelf.recentBookmarks"
+        }
+    }
+
+    static let defaultOrder: [TopShelfSection] = [.continueWatching, .recentFeed, .recentBookmarks]
+}

YatteeTopShelf/TopShelfSnapshot.swift

@@ -0,0 +1,29 @@
+import Foundation
+
+// Must stay in sync with Yattee/Services/TopShelfSnapshot.swift.
+struct TopShelfItem: Codable, Hashable, Sendable {
+    let videoID: String
+    let title: String
+    let authorName: String
+    let duration: TimeInterval
+    let thumbnailURL: String?
+    let deepLinkURL: String
+    let progressSeconds: TimeInterval?
+}
+
+enum TopShelfSnapshot {
+    static func read(section: TopShelfSection, from defaults: UserDefaults = AppGroup.defaults) -> [TopShelfItem] {
+        guard let data = defaults.data(forKey: section.snapshotKey),
+              let items = try? JSONDecoder().decode([TopShelfItem].self, from: data) else {
+            return []
+        }
+        return items
+    }
+
+    static func enabledSections(from defaults: UserDefaults = AppGroup.defaults) -> [TopShelfSection] {
+        guard let raw = defaults.array(forKey: AppGroup.enabledSectionsKey) as? [String] else {
+            return TopShelfSection.defaultOrder
+        }
+        return raw.compactMap { TopShelfSection(rawValue: $0) }
+    }
+}

YatteeTopShelf/YatteeTopShelf.entitlements

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>com.apple.security.application-groups</key>
+	<array>
+		<string>group.stream.yattee.app.shared</string>
+	</array>
+</dict>
+</plist>